Siahaan, Al Ansor, and Muhammad Asrol. “Development of a Machine Learning Model for Predicting Hardness in the Water Treatment Pharmaceutical Industry”. International Journal of Industrial Engineering and Management 14, no. 2 (June 1, 2023): 138–146. Accessed November 15, 2024. http://sp.ftn.uns.ac.rs/index.php/ijiem/article/view/20.